^°^ ZOOLOGY. 



paralleled by the Amphibious; aud urges (hat ouly io the Amphibians 



IS he articular element of themaudibular arcluK^rsistentlycattTlat^u^^^^^ 

 ybile the quadrate ossification is small, and "the sauamnsa ^V? ,' 

 down over it to the osseous elements of the maudiWMbus affS 

 an easy transition to the mammalian condition of these p^rts "' Furthe, 

 "the pectoral arch in the MonotrpmP« it ic oioj i • -t^nrmei, 



tbat of the Amphibians as it i:thrf:;;s uS^^ 



and tarsus of the mammals are directly deSefrirtI,??? 



amphibian type. (It is also suggested th!at it c2r ^Hhl fro ™st 



aortic arch which is L maintnSar't ^1 iZS^g rh:hefrt' 

 ^hile m mammals it is a left aortic arch which perfomfhs office » 



Jf^reS ^f^ irii^tia'^r^y™!^^^^^^ 



and the corresponding- right aortic irnb in +i ^ .i 7 



tlie predominant feedefoflhearteX stem"" ' "'"" '"""^ 



icii^eu bjze and lunctional develoDment of iha i«ff ^4-- , , 



ti%=rora^urra:re £S^^^ 

 ::^LiStrbrrthX^H^T-^^^^^^ 



this stage Will t tud tng™rT;r'n ' 'T™^ "^'-S-S to 

 posed without the amnio,, Jl.f ,f ^'^ ^^ *''*' "'"' *''"'* «»1'- 



tioual branchL wou^dflnd r , ""' "'''"'"""' ""'' I'™"'^'''^ ^'"^ ^unc 



Of descent, frl' Z fr L"«i e'rtet^f :o''tt"'"""'"t '" '"^ ""^ 

 reptiles nor birds wn, M i, I ^"""""'^'^ *« *^o mammals, neither the 



ing "as it we sultac^^^^^^^^^^ ^T""*^ '" ^"^'^^' ^^"--"t- 



termediate between the amnM.tn^T "•^''''""P'"""' <>f tl^at line" in- 



veen the amphibian aud mammalian stages of evolution. 



MAMMALS OF THE AMEEICAN JURASSIC. 



tJw; etS rf'mtmmZ'in the r "''"^ '""'T''""" ^^^"^^""=" 

 ica, although Emmons CuZt!lT ,» , T'" "'^'^^ "^ ^'"rth Amer- 



remains in certaTXL ,n North r r " 't™ "' *■"■" '^'''^^ '"«1 '^A 

 however, quitea nmnltr !f f ?''''''"''• ^" *« '''«' ««™'-''l years, 



lower ja;nrfragrnt;therL'rf:r ''''" "''''"''"'' ^™' "^-l "P™ 

 Territories. Up fo h prZt'tt'e 1^ '''™"! "'"^ '" '"*' ^^^t«™ 

 -^^^;;;jTTf-^--4r-r--^^^— -^^^iii^£^?l^^ representing 



